Etiology of obsessions and compulsions: a meta-analysis and narrative review of twin studies

Towards zebrafish models to unravel translational insights of obsessive-compulsive disorder: A neurobehavioral perspective

Obsessive-compulsive disorder (OCD) is a chronic and debilitating illness that has been considered a polygenic and multifactorial disorder, challenging effective therapeutic interventions. Although invaluable advances have been obtained from human and rodent studies, several molecular and mechanistic aspects of OCD etiology are still obscure. Thus, the use of non-traditional animal models may foster innovative approaches in this field, aiming to elucidate the underlying mechanisms of disease from an evolutionary perspective. The zebrafish (Danio rerio) has been increasingly considered a powerful organism in translational neuroscience research, especially due to the intrinsic features of the species. Here, we outline target mechanisms of OCD for translational research, and discuss how zebrafish-based models can contribute to explore neurobehavioral aspects resembling those found in OCD. We also identify possible advantages and limitations of potential zebrafish-based models, as well as highlight future directions in both etiological and therapeutic research. Lastly, we reinforce the use of zebrafish as a promising tool to unravel the biological basis of OCD, as well as novel pharmacological therapies in the field.

Clinical characteristics of probands with obsessive-compulsive disorder from simplex and multiplex families

Genetic and non-genetic factors contribute to obsessive-compulsive disorder (OCD), with strong evidence of familial clustering. Genomic studies in psychiatry have used the concepts of families that are "simplex" (one affected) versus "multiplex" (multiple affected). Our study compares demographic and clinical data from OCD probands in simplex and multiplex families to uncover potential differences. We analyzed 994 OCD probands (501 multiplex, 493 simplex) from the Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders (C-TOC). Clinicians administered the Structured Clinical Interview for DSM-IV (SCID-IV) to diagnose, Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) to assess severity, and Dimensional Yale-Brown Obsessive-Compulsive Scale (DY-BOCS) to assess symptom dimensionality. Demographics, clinical history, and family data were collected. Compared to simplex probands, multiplex probands had earlier onset, higher sexual/religious and hoarding dimensions severity, increased comorbidity with other obsessive-compulsive-related disorders (OCRD), and higher family history of psychiatric disorders. These comparisons provide the first insights into demographic and clinical differences between Latin American simplex and multiplex families with OCD. Distinct clinical patterns may suggest diverse genetic and environmental influences. Further research is needed to clarify these differences, which have implications for symptom monitoring and management.

Rhesus monkeys exhibiting spontaneous ritualistic behaviors resembling obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a chronic and debilitating psychiatric disorder that affects ∼2%-3% of the population globally. Studying spontaneous OCD-like behaviors in non-human primates may improve our understanding of the disorder. In large rhesus monkey colonies, we found 10 monkeys spontaneously exhibiting persistent sequential motor behaviors (SMBs) in individual-specific sequences that were repetitive, time-consuming and stable over prolonged periods. Genetic analysis revealed severely damaging mutations in genes associated with OCD risk in humans. Brain imaging showed that monkeys with SMBs had larger gray matter (GM) volumes in the left caudate nucleus and lower fractional anisotropy of the corpus callosum. The GM volume of the left caudate nucleus correlated positively with the daily duration of SMBs. Notably, exposure to a stressor (human presence) significantly increased SMBs. In addition, fluoxetine, a serotonergic medication commonly used for OCD, decreased SMBs in these monkeys. These findings provide a novel foundation for developing better understanding and treatment of OCD.

Parenting styles and obsessive-compulsive symptoms in college students: the mediating role of perfectionism

Introduction

Obsessive-compulsive symptoms is a common psychological phenomenon among early adulthood college students, which are closely related to their parents' parenting styles. Theoretical and some empirical studies have suggested the mediating role of perfectionism in this process, but this has not been confirmed, and the binary perspective of positive-negative perfectionism has not been addressed in this issue.

Methods

This study aimed to investigate the mediating role of perfectionism in the relationship between parenting styles and obsessive-compulsive symptoms among college students. A total of 661 college students participated in this study.

Results

Negative perfectionism mediated the relationship between negative parenting style and obsessive-compulsive symptoms among college students. Negative parenting style predicted obsessive-compulsive symptoms through its positive predictive effect on negative perfectionism. However, the mediating effect of positive perfectionism was not significant in this process.

Discussion

This study provides further evidence of the mechanisms underlying the occurrence of obsessive-compulsive symptoms, and offers new ideas for interventions for OCD.

The genetic epidemiology of obsessive-compulsive disorder: a systematic review and meta-analysis

The first systematic review and meta-analysis of obsessive-compulsive disorder (OCD) genetic epidemiology was published approximately 20 years ago. Considering the relevance of all the studies published since 2001, the current study aimed to update the state-of-art knowledge on the field. All published data concerning the genetic epidemiology of OCD from the CENTRAL, MEDLINE, EMBASE, BVS, and OpenGrey databases were searched by two independent researchers until September 30, 2021. To be included, the articles had to fulfill the following criteria: OCD diagnosis provided by standardized and validated instruments; or medical records; inclusion of a control group for comparison and case-control, cohort or twin study designs. The analysis units were the first-degree relatives (FDRs) of OCD or control probands and the co-twins in twin pairs. The outcomes of interest were the familial recurrence rates of OCD and the correlations of OCS in monozygotic compared with dizygotic twins. Nineteen family, twenty-nine twin, and six population-based studies were included. The main findings were that OCD is a prevalent and highly familial disorder, especially among the relatives of children and adolescent probands, that OCD has a phenotypic heritability of around 50%; and that the higher OCS correlations between MZ twins were mainly due to additive genetic or to non-shared environmental components.

Obsessions And Compulsions: A Lifespan Perspective

Freud traced the origin of the obsessional neurosis, which he considered a model condition for psychoanalytic inquiry, to a fixation in the anal phase of psychosexual development. Although many analysts have raised doubts about his account, and while the Sullivanian and Lacanian traditions have proposed alternatives, no approach has accounted for what Freud observed as the dizzying variety of obsessive presentations, which seem to defy a singular explanation. The broader research community has moved on, meanwhile, to genetic, neurological, and cognitive-behavioral explanations of what we now call obsessive-compulsive disorder. I argue that we can best account for the variety of obsessive presentations and meaningfully contribute to this interdisciplinary dialogue by framing obsessive-compulsive symptoms as the result of a disorder of volition, an exaggerated sense of willpower, not tied to any one developmental phase or bodily zone. Such a disorder evolves through the lifespan processes of introjection, identification, and repudiation in relation to an anxious/critical parent or an unpredictable environment. I trace these processes through three major developmental milestones. The implication is that, by looking in depth at how the obsessive person internalizes relationships, psychoanalysis can make a unique contribution to a conversation beyond its own borders.

Epigenetic modifications and obsessive-compulsive disorder: what do we know?

Obsessive-Compulsive Disorder (OCD) is a chronic, severe disabling neuropsychiatric disorder whose pathophysiology is not yet well defined. Generally, the symptom onset occurs during pre-adult life and affects subjects in different life aspects, including professional and social relationships. Although robust evidence indicates the presence of genetic factors in the etiopathology of OCD, the entirely mechanisms are not totally clarified. Thus, the possible interactions between genes and environmental risk factors mediated by epigenetic mechanisms should be sought. Therefore, we provide a review of genetic and epigenetic mechanisms related to OCD with a deep focus on the regulation of critical genes of the central nervous system seeking possible potential biomarkers.

Genetics, sex, and gender

This review aims to give an overview of what has been discovered so far and what still needs to be analyzed about how sex and gender affect the disease development. These two terms are often confused and indifferently used. In principle, the term "sex" refers to biological differences between males and females, specifically reproductive organs and their functions, while the term "gender" refers to the social context in which people live and which contributes to a subjective sexual identity, masculine or feminine. This dichotomy, however, is not so rigid and both sex and gender influence different aspects of human health, such as brain, health and aging and drug treatment and pharmacokinetics. In particular, we want to focus on genetic differences between men and women: indeed, the expression of the genes mapped on X chromosome or Y chromosome and all epigenetic interactions affect the diseases development. Finally, we will briefly outline sex and gender differences in clinical manifestations of three neurological diseases: Alzheimer's disease, Parkinson's disease, and obsessive compulsive disorder. In the era of personalized medicine, we must not forget the importance of gender medicine to promote personalized care for any kind of patients.

Psychological distress modulates dorsal anterior cingulate cortex responses to salient stimuli in obsessive-compulsive disorder

BACKGROUND

Patients with obsessive-compulsive disorder (OCD) experience an exacerbation of symptoms under psychological distress. The neurobiological underpinnings of this effect of stress remain elusive. Here, we induced psychological distress to explore its effect on neural reactivity of the salience network during a symptom provocation task.

METHODS

Twenty-three patients with OCD and twenty-three healthy volunteers underwent functional magnetic resonance imaging scanning after stress induction and a control condition in a cross-over design. Psychological distress was induced using the socially evaluated cold pressor test (SECPT) and neural responses were measured during a symptom provocation task.

RESULTS

OCD participants showed a blunted cortisol response to the stressor. We found a group by stress interaction effect in the dorsal anterior cingulate cortex (dACC), such that psychological distress reduced dACC reactivity to emotionally salient pictures in OCD participants, whereas it increased dACC reactivity in healthy controls.

LIMITATIONS

A considerable proportion of OCD participants was on medication, and the neuroimaging session was conducted more than 1 h after the initial stressor.

CONCLUSIONS

Considering this timeline, we speculate that the blunted dACC reactivity towards emotionally salient pictures in OCD participants may reflect impaired emotion regulation in the aftermath of stress.

Phenotypic Impact of Rare Potentially Damaging Copy Number Variation in Obsessive-Compulsive Disorder and Chronic Tic Disorders

BACKGROUND

Recent studies report an important-and previously underestimated-role of rare variation in risk of obsessive-compulsive disorder (OCD) and chronic tic disorders (CTD). Using data from a large epidemiological study, we evaluate the distribution of potentially damaging copy number variation (pdCNV) in OCD and CTD, examining associations between pdCNV and the phenotypes of probands, including a consideration of early- vs. late-diagnoses.

METHOD

The Obsessive-Compulsive Inventory-Revised (OCI-R) questionnaire was used to ascertain psychometric profiles of OCD probands. CNV were identified genome-wide using chromosomal microarray data.

RESULTS

For 993 OCD cases, 86 (9%) were identified as pdCNV carriers. The most frequent pdCNV found was at the 16p13.11 region. There was no significant association between pdCNV and the OCI-R total score. However, pdCNV was associated with Obsessing and Checking subscores. There was no significant difference in pdCNV frequency between early- vs. late-diagnosed OCD probands. Of the 217 CTD cases, 18 (8%) were identified as pdCNV carriers. CTD probands with pdCNV were significantly more likely to have co-occurring autism spectrum disorder (ASD).

CONCLUSIONS

pdCNV represents part of the risk architecture for OCD and CTD. If replicated, our findings suggest pdCNV impact some OCD symptoms. Genes within the 16p13.11 region are potential OCD risk genes.

The Genetic Architecture of Obsessive-Compulsive Disorder: Contribution of Liability to OCD From Alleles Across the Frequency Spectrum

OBJECTIVE

Obsessive-compulsive disorder (OCD) is known to be substantially heritable; however, the contribution of genetic variation across the allele frequency spectrum to this heritability remains uncertain. The authors used two new homogeneous cohorts to estimate the heritability of OCD from inherited genetic variation and contrasted the results with those of previous studies.

METHODS

The sample consisted of 2,090 Swedish-born individuals diagnosed with OCD and 4,567 control subjects, all genotyped for common genetic variants, specifically >400,000 single-nucleotide polymorphisms (SNPs) with minor allele frequency (MAF) ≥0.01. Using genotypes of these SNPs to estimate distant familial relationships among individuals, the authors estimated the heritability of OCD, both overall and partitioned according to MAF bins.

RESULTS

Narrow-sense heritability of OCD was estimated at 29% (SE=4%). The estimate was robust, varying only modestly under different models. Contrary to an earlier study, however, SNPs with MAF between 0.01 and 0.05 accounted for 10% of heritability, and estimated heritability per MAF bin roughly followed expectations based on a simple model for SNP-based heritability.

CONCLUSIONS

These results indicate that common inherited risk variation (MAF ≥0.01) accounts for most of the heritable variation in OCD. SNPs with low MAF contribute meaningfully to the heritability of OCD, and the results are consistent with expectation under the "infinitesimal model" (also referred to as the "polygenic model"), where risk is influenced by a large number of loci across the genome and across MAF bins.

Association between genetic variants and risk of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a complex multi-gene disorder. In the current study, we genotyped six single nucleotide polymorphisms (SNPs) within MOCOS, NINJ2 and AKT1 genes in a cohort of Iranian patients with this disorder and healthy controls. C allele of rs1057251 has been found to increase risk of OCD (OR (95% CI) =6.39 (4.64-8.79), P value <0.001). This SNP has been associated with risk of OCD in codominant model (OR (95% CI) = 69.53 (25.02-193.21) and 147 (34.2-631.75) for TC and CC genotypes, respectively, P value <0.0001). The rs1057251 was also associated with risk of OCD in dominant (OR (95% CI) = 72.87 (26.28-202.03), P value <0.0001), recessive (OR (95% CI) = 7.43 (2.49-22.19), P value =0.0002), overdominant (OR (95% CI) = 20.2 (11.1-36.76), P value <0.0001) and log-additive (OR (95% CI) = 20.87 (13.83-56.14), P value <0.0001) models. The rs3809263 within NINJ2 was also associated with risk of OCD. The A allele of this SNP has been found to confer risk of OCD (OR (95% CI) =3.28 (2.41-4.48), P value <0.001). This SNP was associated with risk of OCD in codominant (P value <0.0001), dominant (P value <0.0001), overdominant (OR (95% CI) = 9.28 (5.23-16.46), P value<0.0001) and log-additive (OR (95% CI) = 5.25 (3.4-8.1), P value <0.0001) models. Other SNPs were not associated with risk of OCD in any inheritance model. Taken together, rs1057251 and rs3809263 can be considered as risk loci for OCD in Iranian population.

Pandemics and Clinical Psychology

Pandemics are complex events involving a range of stressors affecting mental health. The recent COVID-19 pandemic served as a catalyst, accelerating preexisting trends in clinical care such as the rise of e-health for rapidly and broadly disseminating psychological services. The process of adapting face-to-face clinical services to online formats occurred rapidly during COVID-19, underscoring the adaptability of clinicians to meet new challenges. However, COVID-19 also highlighted important shortcomings in clinical care, including planning deficiencies and shortages of clinicians with specialized training for treating various psychological problems (e.g., prolonged grief disorder). These problems and potential solutions are discussed.

The prefrontal cortex and OCD

Obsessive Compulsive Disorder (OCD) is a highly prevalent and severe neuropsychiatric disorder, with an incidence of 1.5-3% worldwide. However, despite the clear public health burden of OCD and relatively well-defined symptom criteria, effective treatments are still limited, spotlighting the need for investigation of the neural substrates of the disorder. Human neuroimaging studies have consistently highlighted abnormal activity patterns in prefrontal cortex (PFC) regions and connected circuits in OCD during both symptom provocation and performance of neurocognitive tasks. Because of recent technical advances, these findings can now be leveraged to develop novel targeted interventions. Here we will highlight current theories regarding the role of the prefrontal cortex in the generation of OCD symptoms, discuss ways in which this knowledge can be used to improve treatments for this often disabling illness, and lay out challenges in the field for future study.

Changes of Serum Homocysteine and Vitamin B12, but Not Folate Are Correlated With Obsessive-Compulsive Disorder: A Systematic Review and Meta-Analysis of Case-Control Studies

BACKGROUND

Obsessive-compulsive disorder (OCD) a complex neuropsychiatric disorder, is characterized by irresistible obsessive thinking and compulsive behavior. Folate is a member of water-soluble vitamins in the human body and sustains many normal daily activities (e.g., exercise, sleep, and memory). Homocysteine, a sulfur-containing non-essential amino acid, has been investigated in numerous psychiatric disorders (e.g., OCD). Vitamin B12 is a type of complex organic compound with cobalt contained. Moreover, vitamin B12 and folate deficiency and high levels of homocysteine were found to have an effect on brain functions and also lead to non-specific psychiatric symptoms.

OBJECTIVES

This study aimed to confirm the epidemiological evidence of OCD and investigate whether vitamin B12, folate, and homocysteine have an effect on the etiology of OCD.

METHODS

A systematic search was conducted on eight databases (i.e., PubMed, Embase, Web of Science, the Cochrane Library, China Biology Medicine disc, China National Knowledge Infrastructure, Wanfang Database, China Science and Technology Journal Database), and the retrieval time was up to March 2021. The available articles involving patients with OCD with/without abnormal serum levels of vitamin B12, folate, and homocysteine were comprehensively reviewed and analyzed.

RESULTS

A total of 5 studies involving 309 patients were included in this meta-analysis, including 172 cases in the experimental group and 137 in the control group. The content of folate in the OCD group was not significantly different from that in the control group (SMD = -0.089, 95%CI -0.755 to 0.577, p = 0.794). And serum homocysteine was significantly higher in the patients with OCD (SMD = 1.132, 95%CI 0.486 to 1.778, p = 0.001). Vitamin B12 was significantly lower in patients with OCD (SMD = -0.583, 95%CI -0.938 to -0.229, p = 0.001).

CONCLUSIONS

This meta-analysis shows serum high levels of homocysteine, low levels of vitamin B12, and normal folate level are closely correlated with OCD. However, high-quality case-control studies should be further conducted to explore the correlation between serum levels of vitamin B12, folate, homocysteine, and OCD.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021262161; PROSPERO (Number CRD#42021262161).

The Psychology of Pandemics

This article reviews the current state of knowledge and promising new directions concerning the psychology of pandemics. Pandemics are disease outbreaks that spread globally. Historically, psychological factors have been neglected by researchers and health authorities despite evidence that pandemics are, to a large extent, psychological phenomena whereby beliefs and behaviors influence the spreading versus containment of infection. Psychological factors are important in determining (a) adherence to pandemic mitigation methods (e.g., adherence to social distancing), (b) pandemic-related social disruption (e.g., panic buying, racism, antilockdown protests), and (c) pandemic-related distress and related problems (e.g., anxiety, depression, posttraumatic stress disorder, prolonged grief disorder). The psychology of pandemics has emerged as an important field of research and practice during the coronavirus 2019 (COVID-19) pandemic. As a scholarly discipline, the psychology of pandemics is fragmented and diverse, encompassing various psychological subspecialties and allied disciplines, but is vital for shaping clinical practice and public health guidelines for COVID-19 and future pandemics. Expected final online publication date for the Annual Review of Clinical Psychology, Volume 18 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The Role of Stress in Obsessive-Compulsive Disorder: A Narrative Review

Obsessive-compulsive disorder (OCD) has a worldwide prevalence of 2%-3%. Characterized by the presence of either one or two core symptoms-obsessions and compulsions-it generally runs a chronic course and may cause serious functional impairment. Though previously thought to be of psychogenic origin, the pathophysiology of OCD is now understood to be more complex. A multitude of environmental factors have been shown to contribute to the development of OCD, including infection, neonatal complications, childhood trauma, occurrence of stressful events, and brain injury. It has also been proposed that genetic vulnerability may play a role in OCD pathology, although candidate genes have yet to be identified. Likewise, although it is widely accepted that stress plays a role in OCD pathophysiology, the mechanisms remain unclear. Observations from the clinics indicate that stress may serve as both a triggering and aggravating factor, meaning it can prompt symptoms to appear while also contributing to their exacerbation. Additionally, dysfunction of the hypothalamic-pituitary-adrenal axis and impaired stress response have been identified in OCD patients. In this review, we analyze the role of stress in the pathophysiology of OCD, complemented by relevant findings from recent animal studies.

Generalized and social anxiety disorder interactomes show distinctive overlaps with striosome and matrix interactomes

Mechanisms underlying anxiety disorders remain elusive despite the discovery of several associated genes. We constructed the protein-protein interaction networks (interactomes) of six anxiety disorders and noted enrichment for striatal expression among common genes in the interactomes. Five of these interactomes shared distinctive overlaps with the interactomes of genes that were differentially expressed in two striatal compartments (striosomes and matrix). Generalized anxiety disorder and social anxiety disorder interactomes showed exclusive and statistically significant overlaps with the striosome and matrix interactomes, respectively. Systematic gene expression analysis with the anxiety disorder interactomes constrained to contain only those genes that were shared with striatal compartment interactomes revealed a bifurcation among the disorders, which was influenced by the anterior cingulate cortex, nucleus accumbens, amygdala and hippocampus, and the dopaminergic signaling pathway. Our results indicate that the functionally distinct striatal pathways constituted by the striosome and the matrix may influence the etiological differentiation of various anxiety disorders.

Bidirectional Behavioral Selection in Mice: A Novel Pre-clinical Approach to Examining Compulsivity

Obsessive-compulsive disorder (OCD) and related disorders (OCRD) is one of the most prevalent neuropsychiatric disorders with no definitive etiology. The pathophysiological attributes of OCD are driven by a multitude of factors that involve polygenic mechanisms, gender, neurochemistry, physiological status, environmental exposures and complex interactions among these factors. Such complex intertwining of contributing factors imparts clinical heterogeneity to the disorder making it challenging for therapeutic intervention. Mouse strains selected for excessive levels of nest- building behavior exhibit a spontaneous, stable and predictable compulsive-like behavioral phenotype. These compulsive-like mice exhibit heterogeneity in expression of compulsive-like and other adjunct behaviors that might serve as a valuable animal equivalent for examining the interactions of genetics, sex and environmental factors in influencing the pathophysiology of OCD. The current review summarizes the existing findings on the compulsive-like mice that bolster their face, construct and predictive validity for studying various dimensions of compulsive and associated behaviors often reported in clinical OCD and OCRD.

The Role of Antioxidants in the Management of Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is a chronic neuropsychiatric disorder that has a significant effect on the quality of life. The most effective treatment for OCD is the combination of selective serotonin reuptake inhibitors (SSRI) with cognitive behavior therapy (CBT). However, several adverse effects have been linked with this usual pharmacotherapy, and it is unsuccessful in many patients. The exact pathophysiology of OCD is not completely known, though the role of oxidative stress in its pathogenesis has been proposed recently. This review presents an overview of animal and human studies of antioxidant treatment for OCD. The use of antioxidants against oxidative stress is a novel treatment for several neurodegenerative and neuropsychiatric disorders. Among antioxidants, NAC was one of the most studied drugs on OCD, and it showed a significant improvement in OCD symptoms. Thus, antioxidants could be promising as an adjuvant treatment for OCD. However, a limited number of human studies are conducted on these agents, and for better judgment, human studies with a large sample size are necessary.

Genetic and environmental sources of familial coaggregation of obsessive-compulsive disorder and suicidal behavior: a population-based birth cohort and family study

Obsessive-compulsive disorder (OCD) is associated with high risk of suicide. It is yet unknown whether OCD and suicidal behaviors coaggregate in families and, if so, what are the mechanisms underlying this coaggregation. In a population-based birth cohort and family study, we linked individuals born in Sweden in 1967-2003 (n = 3,594,181) to their parents, siblings, and cousins, and collected register-based diagnoses of OCD, suicide attempts, and deaths by suicide and followed them until December 31, 2013. We also applied quantitative genetic modeling to estimate the contribution of genetic and environmental factors to the familial coaggregation of OCD and suicidal behavior. An elevated risk of suicide attempts was observed across all relatives of individuals with OCD, increasing proportionally to the degree of genetic relatedness, with odds ratios (OR) ranging from 1.56 (95% confidence interval (CI) 1.49-1.63) in parents to 1.11 (95% CI 1.07-1.16) in cousins. The risk of death by suicide also increased alongside narrowing genetic distance, but was only significant in parents (OR 1.55; 95% CI 1.40-1.72) and full siblings (OR 1.80; 95% CI 1.43-2.26) of individuals with OCD. Familial coaggregation of OCD and suicide attempts was explained by additive genetic factors (60.7%) and non-shared environment (40.4%), with negligible contribution of shared environment. Similarly, familial coaggregation with death by suicide was attributed to additive genetics (65.8%) and nonshared environment (34.2%). Collectively, these observations indicate that OCD and suicidal behaviors coaggregate in families largely due to genetic factors. The contribution of unique environment is also considerable, providing opportunities to target high-risk groups for prevention and treatment.

Lower excitatory synaptic gene expression in orbitofrontal cortex and striatum in an initial study of subjects with obsessive compulsive disorder

Obsessive compulsive disorder (OCD) is a severe illness that affects 2-3% of people worldwide. OCD neuroimaging studies have consistently shown abnormal activity in brain regions involved in decision-making (orbitofrontal cortex [OFC]) and action selection (striatum). However, little is known regarding molecular changes that may contribute to abnormal function. We therefore examined expression of synaptic genes in post-mortem human brain samples of these regions from eight pairs of unaffected comparison and OCD subjects. Total grey matter tissue samples were obtained from medial OFC (BA11), lateral OFC (BA47), head of caudate, and nucleus accumbens (NAc). Quantitative polymerase chain reaction (qPCR) was then performed on a panel of transcripts encoding proteins related to excitatory synaptic structure, excitatory synaptic receptors/transporters, and GABA synapses. Relative to unaffected comparison subjects, OCD subjects had significantly lower levels of several transcripts related to excitatory signaling in both cortical and striatal regions. However, a majority of transcripts encoding excitatory synaptic proteins were lower in OFC but not significantly different in striatum of OCD subjects. Composite transcript level measures supported these findings by revealing that reductions in transcripts encoding excitatory synaptic structure proteins and excitatory synaptic receptors/transporters occurred primarily in OFC of OCD subjects. In contrast, transcripts associated with inhibitory synaptic neurotransmission showed minor differences between groups. The observed lower levels of multiple glutamatergic transcripts across both medial and lateral OFC may suggest an upstream causal event. Together, these data provide the first evidence of molecular abnormalities in brain regions consistently implicated in OCD human imaging studies.

Familial coaggregation of major psychiatric disorders among first-degree relatives of patients with obsessive-compulsive disorder: a nationwide study

BACKGROUND

Whether the first-degree relatives (FDRs) of patients with obsessive-compulsive disorder (OCD) have an increased risk of the major psychiatric disorders, namely schizophrenia, bipolar disorder, OCD, major depressive disorder (MDD), autism spectrum disorder (ASD), and attention deficit hyperactivity disorder (ADHD), remains unclear.

METHODS

Using the Taiwan National Health Insurance Research Database with the whole population sample size (n = 23 258 175), 89 500 FDRs, including parents, offspring, siblings, and twins, of patients with OCD were identified in our study. The relative risks (RRs) of major psychiatric disorders were assessed among FDRs of patients with OCD.

RESULTS

FDRs of patients with OCD had higher RRs of major psychiatric disorders, namely OCD (RR 8.11, 95% confidence interval (CI) 7.68-8.57), bipolar disorder (RR 2.85, 95% CI 2.68-3.04), MDD (RR 2.67, 95% CI 2.58-2.76), ASD (RR 2.38, 95% CI 2.10-2.71), ADHD (RR 2.19, 95% CI 2.07-2.32), and schizophrenia (RR 1.97, 95% CI 1.86-2.09), compared with the total population. Different familial kinships of FDRs, such as parents, offspring, siblings, and twins consistently had increased risks for these disorders. In addition, a dose-dependent relationship was found between the numbers of OCD probands and the risk of each major psychiatric disorder.

CONCLUSIONS

The FDRs, including parents, offspring, siblings, and twins, of patients with OCD have a higher risk of OCD, schizophrenia, bipolar disorder, MDD, ADHD, and ASD. The familial co-aggregation of OCD with OCD and other major psychiatric disorders was existent in a dose-dependent manner. Given the increased risks of psychiatric disorders, medical practitioners should closely monitor the mental health of the FDRs of patients with OCD.

Neurocognitive Endophenotypes of OCD

In this chapter, I address the concept of endophenotypes for obsessive-compulsive disorder (OCD). Endophenotypes are objective and heritable quantitative traits hypothesized to be more biologically tractable than distal clinical phenotypes. This approach has been adopted to gain a better understanding of psychiatric conditions in general. It is theorized that endophenotypes will particularly assist in clarifying both the diagnostic status and aetiological origins of complex neuropsychiatric conditions such as OCD. At the cognitive level, separable constructs of relevance for OCD have been identified. The prevailing model for OCD assumes the development of abnormalities within fronto-striatal neural circuits leading to impairment of executive functions and their neuropsychological subcomponents. Here, I address whether this model can guide towards the identification of endophenotypes for this condition and discuss possible implications.

Association Between Obsessive-Compulsive Symptom Dimensions in Mothers and Psychopathology in Their Children

Background: The non-clinical presentation of obsessive-compulsive symptoms (OCS) in women may impact not only their daily lives and well-being but also increase the risk for emotional and behavioral problems in their children. This study aims to investigate the OCS dimension distribution in a large sample of mothers from a cohort of school age children and the association between these OCS dimensions with their own psychopathology, and with the presence of OCS and other psychopathology in their children. Method: Our final sample consisted of 2,511 mother-children dyads recruited from the elementary schools of two large cities. Throughout multiple regression analysis, we examined the correlations between demographic and clinical variables of mothers assessed by the Mini International Psychiatric Interview (MINI) and the Dimensional Yale-Brown Obsessive-Compulsive Scale-Short Version (DY-BOCS-SV) with children's psychopathology status reported by the Child Behavior Checklist (CBCL). Results: The overall prevalence of mothers who reported experiencing at least one OCS was 40% (N = 1,004). "Aggression/violence" was the most frequent symptom dimension (32.2%), followed by the "symmetry/ordering" (16.4%) and the "sexual/religious" dimensions (13.8%). There was a significant correlation between the presence of OCS and maternal psychopathology in general (p < 0.001, r = 0.397). Not only the presence but also the severity of the mother's OCS were strongly correlated to the total (p < 0.001), internalizing (p < 0.001), externalizing (p < 0.001), and OCS subscale scores (p < 0.001) on the CBCL. Conclusion: OCS dimensions are highly prevalent in women. Presence and severity of maternal OCS are related to children's psychopathology and behavioral problems.

Risk factors for obsessive-compulsive symptoms. Follow-up of a community-based youth cohort

Environmental factors are at least as important as genetic factors for the development of obsessive-compulsive symptoms (OCS), but the identification of such factors remain a research priority. Our study aimed to investigate the association between a broad scope of potential risk factors and OCS in a large community cohort of children and adolescents. We evaluated 1877 participants and their caregivers at baseline and after 3 years to assess various demographic, prenatal, perinatal, childhood adversity, and psychopathological factors. Mean age at baseline was 10.2 years (SD 1.9) and mean age at follow-up was 13.4 years (SD 1.9). Reports of OCS at baseline and follow-up were analyzed using latent variable models. At preliminary regression analysis, 15 parameters were significantly associated with higher OCS scores at follow-up. At subsequent regression analysis, we found that eight of these parameters remained significantly associated with higher follow-up OCS scores while being controlled by each other and by baseline OCS scores. The significant predictors of follow-up OCS were: lower socioeconomic status (p = 0.033); lower intelligence quotient (p = 0.013); lower age (p < 0.001); higher maternal stress level during pregnancy (p = 0.028); absence of breastfeeding (p = 0.017); parental baseline OCS (p = 0.038); youth baseline anxiety disorder (p = 0.023); and youth baseline OCS scores (p < 0.001). These findings may better inform clinicians and policymakers engaged in the mental health assessment and prevention in children and adolescents.

Animal Models for OCD Research

OCD has lagged behind other psychiatric illnesses in the identification of molecular treatment targets, due in part to a lack of significant findings in genome-wide association studies. However, while progress in this area is being made, OCD's symptoms of obsessions, compulsions, and anxiety can be deconstructed into distinct neural functions that can be dissected in animal models. Studies in rodents and non-human primates have highlighted the importance of cortico-basal ganglia-thalamic circuits in OCD pathophysiology, and emerging studies in human post-mortem brain tissue point to glutamatergic synapse abnormalities as a potential cellular substrate for observed dysfunctional behaviors. In addition, accumulated evidence points to a potential role for neuromodulators including serotonin and dopamine in both OCD pathology and treatment. Here, we review current efforts to use animal models for the identification of molecules, cell types, and circuits relevant to OCD pathophysiology. We start by describing features of OCD that can be modeled in animals, including circuit abnormalities and genetic findings. We then review different strategies that have been used to study OCD using animal model systems, including transgenic models, circuit manipulations, and dissection of OCD-relevant neural constructs. Finally, we discuss how these findings may ultimately help to develop new treatment strategies for OCD and other related disorders.

The association of HTR2A polymorphisms with obsessive-compulsive disorder and its subtypes: A meta-analysis

BACKGROUND

Genetic risk factors that contribute to obsessive-compulsive disorder (OCD) have yet to be elucidated. Historically, serotonergic dysfunction has been implicated. Evidence from the literature points towards the serotonin receptor 2A gene (HTR2A) as a primary candidate. Our meta-analysis investigated whether polymorphisms in HTR2A are associated with OCD or its subtypes, based on sex and age of onset.

METHODS

Studies employing case-control or family-based designs were systematically searched, and those meeting eligibility underwent quality assessment, resulting in 18 studies. A random-effects meta-analysis using standard inverse-variance weighting to compute odds ratio (OR) was conducted. To examine sensitivity, results were also obtained using a more conservative statistical method.

RESULTS

Three HTR2A variants were identified: T102C, G-1438A, and C516T. T102C and G-1438A were analyzed together due to strong linkage disequilibrium, where the 102T allele co-occurs with -1438A allele. Results reported as OR [95%CI] showed that the T/A allele were significantly associated with OCD, 1.14 [1.01, 1.29]. After stratification, results remained significant for females, 1.20 [1.00, 1.45], and early-onset OCD, 1.27 [1.02, 1.58], but not males, 1.06 [0.91, 1.23]. No associations were found for late-onset OCD, 0.98 [0.70, 1.37], or C516T, 1.22 [0.14, 10.37], but conclusions cannot be drawn from two studies.

LIMITATIONS

Associations no longer reached significance with the conservative statistical approach. HTR2A alone cannot explain OCD complexity and limited samples reporting genetic data according to subtypes.

CONCLUSIONS

These results suggest a possible association of HTR2A polymorphisms with OCD, but further investigations considering sex and age of onset with larger samples is needed.

Dysregulated plasma levels of miRNA-132 and miRNA-134 in patients with obsessive-compulsive disorder

Background

Obsessive-compulsive disorder (OCD) is a severe, chronic, disabling neuropsychiatric disorder, the pathophysiology of which has yet to be fully understood. In this study, we aimed to detect the levels of miRNA-132 and miRNA-134 in the plasma of patients with OCD and to analyze the factors influencing OCD.

Methods

The levels of miRNA-132 and miRNA-134 in peripheral blood of 30 patients with OCD and 32 normal controls were detected by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Patients were assessed using clinical scales, including the Hamilton Anxiety Rating Scale (HAMA), Hamilton Depression Rating Scale (HAMD), and Yale-Brown Obsessive-Compulsive Scale (Y-BOCS).

Results

The plasma levels of miRNA-132 and miRNA 134 in the OCD group were significantly higher than those in the control group (P<0.05). There was no significant correlation between the plasma levels of miR-132 and miR-134 in the OCD group and general demographic (gender, age, and education level) and clinical characteristics (duration of disease, HAMA, HAMD, and Y-BOCS scores).

Conclusions

Patients with OCD have abnormal plasma levels of miRNA-132 and miRNA-134, which may influence the number of dendrites in the cerebral cortex and formation of synapses. Therefore, miRNA-132 and miRNA-134 plasma levels should be considered as potential biomarkers for OCD detection.

Heritability of overlapping impulsivity and compulsivity dimensional phenotypes

Impulsivity and compulsivity are traits relevant to a range of mental health problems and have traditionally been conceptualised as distinct constructs. Here, we reconceptualised impulsivity and compulsivity as partially overlapping phenotypes using a bifactor modelling approach and estimated heritability for their shared and unique phenotypic variance within a classical twin design. Adult twin pairs (N = 173) completed self-report questionnaires measuring psychological processes related to impulsivity and compulsivity. We fitted variance components models to three uncorrelated phenotypic dimensions: a general impulsive-compulsive dimension; and two narrower phenotypes related to impulsivity and obsessiveness.There was evidence of moderate heritability for impulsivity (A² = 0.33), modest additive genetic or common environmental effects for obsessiveness (A² = 0.25; C² = 0.23), and moderate effects of common environment (C² = 0.36) for the general dimension, This general impulsive-compulsive phenotype may reflect a quantitative liability to related mental health disorders that indexes exposure to potentially modifiable environmental risk factors.

Obsessive-compulsive disorder and attention-deficit/hyperactivity disorder: distinct associations with DNA methylation and genetic variation

BACKGROUND

A growing body of research has demonstrated associations between specific neurodevelopmental disorders and variation in DNA methylation (DNAm), implicating this molecular mark as a possible contributor to the molecular etiology of these disorders and/or as a novel disease biomarker. Furthermore, genetic risk variants of neurodevelopmental disorders have been found to be enriched at loci associated with DNAm patterns, referred to as methylation quantitative trait loci (mQTLs).

METHODS

We conducted two epigenome-wide association studies in individuals with attention-deficit/hyperactivity disorder (ADHD) or obsessive-compulsive disorder (OCD) (aged 4-18 years) using DNA extracted from saliva. DNAm data generated on the Illumina Human Methylation 450 K array were used to examine the interaction between genetic variation and DNAm patterns associated with these disorders.

RESULTS

Using linear regression followed by principal component analysis, individuals with the most endorsed symptoms of ADHD or OCD were found to have significantly more distinct DNAm patterns from controls, as compared to all cases. This suggested that the phenotypic heterogeneity of these disorders is reflected in altered DNAm at specific sites. Further investigations of the DNAm sites associated with each disorder revealed that despite little overlap of these DNAm sites across the two disorders, both disorders were significantly enriched for mQTLs within our sample.

CONCLUSIONS

Our DNAm data provide insights into the regulatory changes associated with genetic variation, highlighting their potential utility both in directing GWAS and in elucidating the pathophysiology of neurodevelopmental disorders.

De Novo Damaging DNA Coding Mutations Are Associated With Obsessive-Compulsive Disorder and Overlap With Tourette's Disorder and Autism

BACKGROUND

Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric disorder with a genetic risk component, yet identification of high-confidence risk genes has been challenging. In recent years, risk gene discovery in other complex psychiatric disorders has been achieved by studying rare de novo (DN) coding variants.

METHODS

We performed whole-exome sequencing in 222 OCD parent-child trios (184 trios after quality control), comparing DN variant frequencies with 777 previously sequenced unaffected trios. We estimated the contribution of DN mutations to OCD risk and the number of genes involved. Finally, we looked for gene enrichment in other datasets and canonical pathways.

RESULTS

DN likely gene disrupting and predicted damaging missense variants are enriched in OCD probands (rate ratio, 1.52; p = .0005) and contribute to risk. We identified 2 high-confidence risk genes, each containing 2 DN damaging variants in unrelated probands: CHD8 and SCUBE1. We estimate that 34% of DN damaging variants in OCD contribute to risk and that DN damaging variants in approximately 335 genes contribute to risk in 22% of OCD cases. Furthermore, genes harboring DN damaging variants in OCD are enriched for those reported in neurodevelopmental disorders, particularly Tourette's disorder and autism spectrum disorder. An exploratory network analysis reveals significant functional connectivity and enrichment in canonical pathways, biological processes, and disease networks.

CONCLUSIONS

Our findings show a pathway toward systematic gene discovery in OCD via identification of DN damaging variants. Sequencing larger cohorts of OCD parent-child trios will reveal more OCD risk genes and will provide needed insights into underlying disease biology.

Maternal Effects as Causes of Risk for Obsessive-Compulsive Disorder

BACKGROUND

While genetic variation has a known impact on the risk for obsessive-compulsive disorder (OCD), there is also evidence that there are maternal components to this risk. Here, we partitioned sources of variation, including direct genetic and maternal effects, on risk for OCD.

METHODS

The study population consisted of 822,843 individuals from the Swedish Medical Birth Register, born in Sweden between January 1, 1982, and December 31, 1990, and followed for a diagnosis of OCD through December 31, 2013. Diagnostic information about OCD was obtained using the Swedish National Patient Register.

RESULTS

A total of 7184 individuals in the birth cohort (0.87%) were diagnosed with OCD. After exploring various generalized linear mixed models to fit the diagnostic data, genetic maternal effects accounted for 7.6% (95% credible interval: 6.9%-8.3%) of the total variance in risk for OCD for the best model, and direct additive genetics accounted for 35% (95% credible interval: 32.3%-36.9%). These findings were robust under alternative models.

CONCLUSIONS

Our results establish genetic maternal effects as influencing risk for OCD in offspring. We also show that additive genetic effects in OCD are overestimated when maternal effects are not modeled.

Mental health dished up-the use of iPSC models in neuropsychiatric research

Genetic and molecular mechanisms that play a causal role in mental illnesses are challenging to elucidate, particularly as there is a lack of relevant in vitro and in vivo models. However, the advent of induced pluripotent stem cell (iPSC) technology has provided researchers with a novel toolbox. We conducted a systematic review using the PRISMA statement. A PubMed and Web of Science online search was performed (studies published between 2006–2020) using the following search strategy: hiPSC OR iPSC OR iPS OR stem cells AND schizophrenia disorder OR personality disorder OR antisocial personality disorder OR psychopathy OR bipolar disorder OR major depressive disorder OR obsessive compulsive disorder OR anxiety disorder OR substance use disorder OR alcohol use disorder OR nicotine use disorder OR opioid use disorder OR eating disorder OR anorexia nervosa OR attention-deficit/hyperactivity disorder OR gaming disorder. Using the above search criteria, a total of 3515 studies were found. After screening, a final total of 56 studies were deemed eligible for inclusion in our study. Using iPSC technology, psychiatric disease can be studied in the context of a patient’s own unique genetic background. This has allowed great strides to be made into uncovering the etiology of psychiatric disease, as well as providing a unique paradigm for drug testing. However, there is a lack of data for certain psychiatric disorders and several limitations to present iPSC-based studies, leading us to discuss how this field may progress in the next years to increase its utility in the battle to understand psychiatric disease.

Shared genetic etiology between obsessive-compulsive disorder, obsessive-compulsive symptoms in the population, and insulin signaling

Obsessive-compulsive symptoms (OCS) in the population have been linked to obsessive-compulsive disorder (OCD) in genetic and epidemiological studies. Insulin signaling has been implicated in OCD. We extend previous work by assessing genetic overlap between OCD, population-based OCS, and central nervous system (CNS) and peripheral insulin signaling. We conducted genome-wide association studies (GWASs) in the population-based Philadelphia Neurodevelopmental Cohort (PNC, 650 children and adolescents) of the total OCS score and six OCS factors from an exploratory factor analysis of 22 questions. Subsequently, we performed polygenic risk score (PRS)-based analysis to assess shared genetic etiologies between clinical OCD (using GWAS data from the Psychiatric Genomics Consortium), the total OCS score and OCS factors. We then performed gene-set analyses with a set of OCD-linked genes centered around CNS insulin-regulated synaptic function and PRS-based analyses for five peripheral insulin signaling-related traits. For validation purposes, we explored data from the independent Spit for Science population cohort (5,047 children and adolescents). In the PNC, we found a significant shared genetic etiology between OCD and 'guilty taboo thoughts'. In the Spit for Science cohort, we additionally observed genetic sharing between 'symmetry/counting/ordering' and 'contamination/cleaning'. The CNS insulin-linked gene-set also associated with 'symmetry/counting/ordering' in the PNC. Further, we identified genetic sharing between peripheral insulin signaling-related traits: type 2 diabetes with 'aggressive taboo thoughts', and levels of fasting insulin and 2 h glucose with OCD. In conclusion, OCD, OCS in the population and insulin-related traits share genetic risk factors, indicating a common etiological mechanism underlying somatic and psychiatric disorders.

Interaction between PGRN gene and the early trauma on clinical characteristics in patients with obsessive-compulsive disorder

BACKGROUND

Emerging evidence suggests that obsessive-compulsive disorder (OCD) is caused by a combination of genetic predisposition and environmental factors. In this regard, abnormity of progranulin (PGRN, a key regulator of brain inflammation) and a history of childhood trauma have both been linked to an increased risk of developing OCD. This study is aimed to investigate the association between PGRN and childhood trauma in the development of OCD.

METHODS

We genotyped four single nucleotide polymorphisms (SNPs) covering PGRN in 484 OCD patients and 368 healthy controls. Among the OCD patients, 335 of them accepted clinical assessments in details. Generalized multifactor dimensionality reduction (GDMR) analysis and a general linear model were used to identify gene-environment interactions. The Braineac expression Quantitative Trait Loci (eQTL) dataset was used to analyze the differences in PGRN expression in various brain regions among different genotypes.

RESULTS

Our linkage disequilibrium analysis revealed that rs3859268-rs2879096-rs3785817 combined OCD and control groups constructed one haplotype block. The haplotype analysis suggested that TCA haplotype frequency was associated with the risk of developing OCD (Padj=0.03). The Braineac eQTL database revealed that rs2879096 and rs3785817 might be associated with PGRN expression in the hippocampus (Padj=0.00085, Padj=0.007). Emotional abuse was positively correlated with the obsession subscale and Y-BOCS total scores. Except for common trauma, physical abuse, emotional abuse and sexual trauma were all positively correlated with the BAI and BDI-II scores of OCD patients (all P<0.05). The interaction between emotional abuse and PGRN haplotype was associated with the development of depression symptoms in OCD patients corrected by age (Padj=0.043).

CONCLUSIONS

The PGRN gene and childhood trauma may be closely related to the incidence of OCD, and OCD patients who have experienced more childhood trauma may exhibit a more severe clinical symptom. The interaction between PGRN and the early trauma may play a critical role in the development of depression symptom in OCD patients.

Prevalence and Characteristics of Obsessive-Compulsive Disorder Among Urban Residents in Wuhan During the Stage of Regular Control of Coronavirus Disease-19 Epidemic

Background: Coronavirus disease-19 (Covid-19) is one of the most devastating epidemics in the 21st century, which has caused considerable damage to the physical and mental health of human beings. Despite a few regions like China having controlled the epidemic trends, most countries are still under siege of COVID-19. As the emphasis on cleaning and hygiene has been increasing, the problems related to obsessive-compulsive disorder (OCD) may appear. Objective: This study was designed to investigate the prevalence of OCD in the urban population in Wuhan during the stage of regular epidemic control and prevention. Meanwhile, characteristics and risk factors for OCD were also explored. Method: Five-hundred and seventy residents in urban areas of Wuhan were recruited using the snowball sampling method to complete questionnaires and an online interview from July 9 to July 19, 2020. Collected information encompassed socio-demographics, Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores, Social Support Rating Scale (SSRS) scores and Pittsburgh Sleep Quality Index(PSQI) values. Results: Three months after lifting the quarantine in Wuhan, the prevalence of OCD was 17.93%. About 89% of OCD patients had both obsessions and compulsions, while 8% had only obsessions and 3% had only compulsions. Top 3 common dimensions of obsessions were miscellaneous (84.0%), aggressive (76.6%), and contamination (48.9%), and of compulsions were miscellaneous (64%), checking (51.7%), and cleaning/washing/repeating (31.5%). The unmarried were more vulnerable to OCD than the married (p < 0.05, odds ration = 1.836). Students had 2.103 times the risk of developing OCD than health care workers (p < 0.05). Those with positive family history of OCD and other mental disorders (p < 0.05, odds ration = 2.497) and presence of psychiatric comorbidity (p < 0.05, odds ration = 4.213) were also at higher risk. Each level increase in sleep latency increased the risk of OCD to 1.646 times (p < 0.05). Conclusion: In the background of regular epidemic control, the prevalence of OCD was high, and the symptoms were widely distributed. Obsessions often accompanied compulsions. Being single and a student, positive family history of OCD and other mental disorders, presence of psychiatric comorbidity, and longer sleep latency were predictors of OCD. Early recognition and detection of these issues may help to intervene in OCD.

Mental health is biological health: Why tackling "diseases of the mind" is an imperative for biological anthropology in the 21st century

The germ theory of disease and the attendant public health initiatives, including sanitation, vaccination, and antibiotic treatment, led to dramatic increases in global life expectancy. As the prevalence of infectious disease declines, mental disorders are emerging as major contributors to the global burden of disease. Scientists understand little about the etiology of mental disorders, however, and many of the most popular psychopharmacological treatments, such as antidepressants and antipsychotics, have only moderate-to-weak efficacy in treating symptoms and fail to target biological systems that correspond to discrete psychiatric syndromes. Consequently, despite dramatic increases in the treatment of some mental disorders, there has been no decrease in the prevalence of most mental disorders since accurate record keeping began. Many researchers and theorists are therefore endeavoring to rethink psychiatry from the ground-up. Anthropology, especially biological anthropology, can offer critical theoretical and empirical insights to combat mental illness globally. Biological anthropologists are unique in that we take a panhuman approach to human health and behavior and are trained to address each of Tinbergen's four levels of analysis as well as culture. The field is thus exceptionally well-situated to help resolve the mysteries of mental illness by integrating biological, evolutionary, and sociocultural perspectives.

Relationship between obsessive compulsive disorder and cortisol: Systematic review and meta-analysis

Altered stress response and consequent elevated levels of circulating glucocorticoids have been found in neuropsychiatric disorders such as depression or anxiety disorders and proposed to also play a role in the pathophysiology of obsessive-compulsive disorder (OCD). Despite the observation that stressful events may precede the disease onset or even exacerbate its symptoms, studies in this field do not always report consistent results regarding the cortisol profile of OCD patients. As such, a systematic review and meta-analysis was developed to clarify this issue. This systematic review and meta-analysis was elaborated according to the PRISMA method. The analytical procedures were implemented using Metafor package in R software. Nineteen studies were included in the systematic review and 18 were included in the meta-analysis. The meta-analytic results demonstrated that OCD patients had significantly higher cortisol levels compared to controls (d = 0.76, SE = 0.146, p < 0.001). For studies using the average of multiple assessments, the standardized coefficient was significantly higher when compared to studies focusing on single measurements. Both the systematic review and meta-analysis suggest that cortisol levels are significantly higher in OCD patients than healthy individuals.

Converging evidence points towards a role of insulin signaling in regulating compulsive behavior

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder with childhood onset, and is characterized by intrusive thoughts and fears (obsessions) that lead to repetitive behaviors (compulsions). Previously, we identified insulin signaling being associated with OCD and here, we aim to further investigate this link in vivo. We studied TALLYHO/JngJ (TH) mice, a model of type 2 diabetes mellitus, to (1) assess compulsive and anxious behaviors, (2) determine neuro-metabolite levels by 1 H magnetic resonance spectroscopy (MRS) and brain structural connectivity by diffusion tensor imaging (DTI), and (3) investigate plasma and brain protein levels for molecules previously associated with OCD (insulin, Igf1, Kcnq1, and Bdnf) in these subjects. TH mice showed increased compulsivity-like behavior (reduced spontaneous alternation in the Y-maze) and more anxiety (less time spent in the open arms of the elevated plus maze). In parallel, their brains differed in the white matter microstructure measures fractional anisotropy (FA) and mean diffusivity (MD) in the midline corpus callosum (increased FA and decreased MD), in myelinated fibers of the dorsomedial striatum (decreased FA and MD), and superior cerebellar peduncles (decreased FA and MD). MRS revealed increased glucose levels in the dorsomedial striatum and increased glutathione levels in the anterior cingulate cortex in the TH mice relative to their controls. Igf1 expression was reduced in the cerebellum of TH mice but increased in the plasma. In conclusion, our data indicates a role of (abnormal) insulin signaling in compulsivity-like behavior.

Obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a highly prevalent and chronic condition that is associated with substantial global disability. OCD is the key example of the 'obsessive-compulsive and related disorders', a group of conditions which are now classified together in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, and the International Classification of Diseases, 11th Revision, and which are often underdiagnosed and undertreated. In addition, OCD is an important example of a neuropsychiatric disorder in which rigorous research on phenomenology, psychobiology, pharmacotherapy and psychotherapy has contributed to better recognition, assessment and outcomes. Although OCD is a relatively homogenous disorder with similar symptom dimensions globally, individualized assessment of symptoms, the degree of insight, and the extent of comorbidity is needed. Several neurobiological mechanisms underlying OCD have been identified, including specific brain circuits that underpin OCD. In addition, laboratory models have demonstrated how cellular and molecular dysfunction underpins repetitive stereotyped behaviours, and the genetic architecture of OCD is increasingly understood. Effective treatments for OCD include serotonin reuptake inhibitors and cognitive-behavioural therapy, and neurosurgery for those with intractable symptoms. Integration of global mental health and translational neuroscience approaches could further advance knowledge on OCD and improve clinical outcomes.

A Clinical Staging Model for Obsessive-Compulsive Disorder: Is It Ready for Prime Time?

Recent changes to the diagnostic classification of obsessive-compulsive disorder (OCD), including its removal from the anxiety/neurotic, stress-related and somatoform disorders chapters of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and International Classification of Diseases 11th Revision (ICD-11), are based on growing evidence of unique pathogenic signatures and linked diagnostic and treatment approaches. In this review, we build on these recent developments and propose a 'clinical staging model' of OCD that integrates the severity of symptoms and phase of illness for personalised case management. A clinical staging model is especially relevant for the early identification and management of subthreshold OCD - a substantial and largely neglected portion of the population who, despite having milder symptoms, experience harms that may impact personal relationships, work-related functioning and productivity. Research on the pathogenesis, classification and management of such cases is needed, including the development of new outcomes measures that prove sensitive to changes in future clinical trials. Early intervention strategies in OCD are likely to yield better long-term outcomes.

Heritability of obsessive-compulsive trait dimensions in youth from the general population

Obsessive-compulsive disorder (OCD) is a heritable childhood-onset psychiatric disorder that may represent the extreme of obsessive-compulsive (OC) traits that are widespread in the general population. We report the heritability of the Toronto Obsessive-Compulsive Scale (TOCS), a new measure designed to assess the complete range of OC traits in youth. We also examined the dimensional nature of the TOCS and the degree to which genetic effects are unique or shared between dimensions. OC traits were measured using the TOCS in 16,718 youth (6-18 years) at a science museum. We conducted a factor analysis to identify OC trait dimensions. We used univariate and multivariate twin models to estimate the heritability of OC trait dimensions in a subset of twins (220 pairs). Six OC dimensions were identified: Cleaning/Contamination, Symmetry/Ordering, Rumination, Superstition, Counting/Checking, and Hoarding. The TOCS total score (74%) and each OC dimension was heritable (30-77%). Hoarding was not highly correlated with other OC dimensions, but did share genetic effects. Shared genetics accounted for most of the shared variance among dimensions, whereas unique environment accounted for the majority of dimension-specific variance. One exception was Hoarding, which had considerable unique genetic factors. A latent trait did not account for the shared variance between dimensions. In conclusion, OC traits and individual OC dimensions were heritable, although the degree of shared and dimension-specific etiological factors varied by dimension. The TOCS may be informative for genetic research of OC traits in youth. Genetic research of OC traits should consider both OC dimension and total trait scores.

Revealing the complex genetic architecture of obsessive-compulsive disorder using meta-analysis

Two obsessive-compulsive disorder (OCD) genome-wide association studies (GWASs) have been published by independent OCD consortia, the International Obsessive-Compulsive Disorder Foundation Genetics Collaborative (IOCDF-GC) and the OCD Collaborative Genetics Association Study (OCGAS), but many of the top-ranked signals were supported in only one study. We therefore conducted a meta-analysis from the two consortia, investigating a total of 2688 individuals of European ancestry with OCD and 7037 genomically matched controls. No single-nucleotide polymorphisms (SNPs) reached genome-wide significance. However, in comparison with the two individual GWASs, the distribution of P-values shifted toward significance. The top haplotypic blocks were tagged with rs4733767 (P=7.1 × 10^-7; odds ratio (OR)=1.21; confidence interval (CI): 1.12-1.31, CASC8/CASC11), rs1030757 (P=1.1 × 10^-6; OR=1.18; CI: 1.10-1.26, GRID2) and rs12504244 (P=1.6 × 10^-6; OR=1.18; CI: 1.11-1.27, KIT). Variants located in or near the genes ASB13, RSPO4, DLGAP1, PTPRD, GRIK2, FAIM2 and CDH20, identified in linkage peaks and the original GWASs, were among the top signals. Polygenic risk scores for each individual study predicted case-control status in the other by explaining 0.9% (P=0.003) and 0.3% (P=0.0009) of the phenotypic variance in OCGAS and the European IOCDF-GC target samples, respectively. The common SNP heritability in the combined OCGAS and IOCDF-GC sample was estimated to be 0.28 (s.e.=0.04). Strikingly, ∼65% of the SNP-based heritability in the OCGAS sample was accounted for by SNPs with minor allele frequencies of ⩾40%. This joint analysis constituting the largest single OCD genome-wide study to date represents a major integrative step in elucidating the genetic causes of OCD.

Children's Naive Concepts of OCD and How They Are Affected by Biomedical Versus Cognitive Behavioural Psychoeducation

BACKGROUND

How we conceptualize mental health conditions is important as it impacts on a wide range of mediators of treatment outcome. We do not know how children intuitively conceptualize obsessive-compulsive disorder (OCD), nor do we know the relative impact of biomedical or cognitive behavioural conceptual explanations, yet both are being widely used in psychoeducation for children with OCD.

AIMS

This study identified children's naive concepts of OCD, and the comparative impact of biomedical versus cognitive behavioural psychoeducation on perceived prognosis.

METHOD

A within- and between-subjects experimental design was used. After watching a video of a young person describing their OCD, 202 children completed a questionnaire examining their concepts of the condition. They repeated the questionnaire following a second equivalent video, this time preceded by either biomedical or cognitive behavioural psychoeducation.

RESULTS

Participants' naive concepts of OCD reflected predominant models of OCD in healthcare. Even at the minimal dose of psychoeducation, participants' conceptualizations of OCD changed. Prior exposure to OCD resulted in a stronger alignment with the biomedical model. Exposure to biomedical psychoeducation resulted in participants predicting a slower recovery with less chance of complete remission.

CONCLUSION

Psychoeducation for childhood OCD is impactful. Despite its wide use by clinicians and mental health services, biomedical psychoeducation appears to have deleterious effects. Children's concepts of OCD merit attention but caution should be applied in how they are targeted.